It's been a while since we've had either a Food Pyramid or Alzheimer's update, and now we have a two-fer:
Past studies have linked caffeine with lowering the risk of developing Alzheimer's; this one actually concludes that it can "directly target the disease itself." The mice involved in the study actually demonstrated increased mental skills. How this will translate to humans, of course, is yet to be seen.
(In fairness, the scientists were really studying the effects of caffeine, not coffee per se: the mice were given caffeinated water. But they didn't say coffee wouldn't work just as well)